The present invention relates generally to surgical instruments for occluding a vessel or other body conduit, and more particularly, to replaceable pads or inserts for attachment to jaw-type occlusion devices.
Instruments for occluding blood vessels and other body conduits are well known. Conventional surgical clamps or clips are often made of metal, such as stainless steel, or other similarly rigid materials. Such surgical clamps are favored for a number of reasons. They can be manufactured to have a low profile, and the overall structural rigidity of the clamps together with the non-deflectable and non-deformable gripping surfaces provides a clamp having excellent gripping properties. Gripping can be further improved by providing surface irregularities to the gripping surfaces, such as scoring the surface or otherwise including serrations, teeth, or other raised protrusions. As one such example, U.S. Pat. No. 3,515,139 to Mallina discloses surgical forceps with hard plastic inserts having spherical protuberances and complementary grooves or spherical cavities. A disadvantage, however, of such clamps is that the hard surfaces and rigidity of the clamps can cause trauma to the clamped vessel at the clamping site.
As a result, a number of atraumatic instruments have been developed for reducing trauma to a vessel during occlusion. In particular, conventional surgical clamps and clips have been adapted to include jaw surfaces containing resilient members or pads. These devices likewise have their disadvantages. For example, these devices are prone to slipping off of the clamped vessel. This can be especially problematic in situations where, due to obstructions, a vessel has been clamped with only the distal tips of the clamp jaws. In such situations, the vessel can be especially prone to slipping in the direction of the distal tips. Also, due to the deformability of such pads or members, such pads or members are prone to slipping laterally on a clamped vessel, resulting in a xe2x80x9cscissor-likexe2x80x9d effect where the jaws can twist off-line. In such a situation, effective clamping of the vessel is compromised.
Other attempts have thus been made to atraumatically occlude a vessel in a more secure fashion. U.S. Pat. No. 3,746,002 to Hailer discloses a vascular clamp with resilient gripping members on the jaws that are formed of a resilient material having a plurality of hard pin members embedded therein. The pin members are of a length such that when a vessel is clamped between the gripping members, the resilient material deflects to accommodate the vessel, exposing the pin members which grippingly engage the outer layer of the vessel, thus securing the vessel to the gripping member. While the Haller device is less traumatic to a vessel than other occlusion devices, it nevertheless has the disadvantage of traumatizing the outer layer of the vessel.
U.S. Pat. No. 3,503,397 to Fogarty discloses surgical clamps with jaw inserts having hard plastic teeth along the edges of the insert with a softer component along the interior of the insert. The hard teeth of this device serve to resist movement of a clamped vessel laterally of the jaw, but again do so at increased risk of trauma to the vessel. Still further attempts have been made to atraumatically occlude a vessel, such as those disclosed in PCT Publication WO 99/11179.
There thus remains a need for a surgical clamp which atraumatically occludes vessels with improved gripping capabilities while simultaneously avoiding the disadvantages previously associated with existing surgical clamps or occlusion devices.
The present invention meets these and other needs and provides for replaceable surgical clamp pads or inserts having a compliant cushion and a flexible non-compliant overlay secured onto the cushion surface for engagement with a vessel or other body tissue. Various attaching structures can be provided on the cushion for securing the pad or insert onto the clamp jaw.
In one aspect of the invention, the overlay can entirely cover the cushion surface. In another aspect of the invention, a series of notches can be provided along the sides of the overlay to increase the flexibility of the overlay. The combination of surface overlay and underlying compliant cushion results in an insert that as a whole deflects to accommodate a clamped vessel while providing surface clamping characteristics associated with conventional clamps. The deflection of the insert, which is a function of the underlying compliant cushion, reduces trauma to the clamped vessel. At the same time, the non-compliant overlay provides a non-deformable clamping surface similar to that provided by conventional rigid metal or hard plastic clamps, thereby providing gripping characteristics approximating conventional rigid metal or hard plastic clamps.
In one embodiment of the invention, the overlay can be formed of a metal, such as stainless steel. In another embodiment of the invention, the overlay can be formed of a thermoplastic.
In another aspect of the invention, the overlay itself can be provided with a textured surface having surface irregularities to provide for increased traction between the overlay and the engaged vessel or body tissue. In one such embodiment the overlay can include protrusions extending from the overlay surface. In another such embodiment, such protrusions can be in the form of a plurality of columns extending from the overlay in a direction generally perpendicular to the cushion surface. In yet another such embodiment, the surface overlay can include a multiplicity of perforations.
Methods of manufacturing the replaceable pad or inserts of the present invention are also provided.